Development and validation of an integrated computational model of cerebral blood flow and oxygenation.

Abstract

Various groups have constructed simulations and models of cerebral blood flow and oxygenation, each with its strengths and weaknesses. We describe the development and validation of a novel computational model, the Nottingham cerebral simulator (NCS), designed for experimental and teaching use. Physiological hypotheses were converted into differential equations; these are solved numerically with respect to time. A battery of tests was derived from published literature against which to test the simulation: static and dynamic autoregulation responses; carbon dioxide reactivity; brain tissue oxygenation. The NCS was programmed to simulate the methodologies of published experiments and the results of the simulation and the published data were compared. The NCS results are qualitatively and quantitatively similar to published data. The values for regulatory indices were (published values in parentheses): index of autoregulation 0.9 (0.9); transient hyperemic response ratio 1.3 (1.3), carbon dioxide reactivity 2.4%-4.7% mm Hg(-1) (2-4.5); brain tissue oxygen tension 22 mm Hg (20-100). The NCS is a credible model of cerebral blood flow and oxygenation, which warrants further use as an experimental and teaching tool.